fix(sheets): make --max-chars the single read cap for +cells-get / +csv-get

Drop --cell-limit (+cells-get) and --max-rows (+csv-get) from the CLI surface
and pin the underlying tool's cell_limit / max_rows to a very large sentinel so
the tool's own defaults never truncate before --max-chars. --max-chars stays the
only knob (default 200000, unchanged).

- lark_sheet_read_data.go: add unboundedReadLimit (1e9); cellsGetInput pins
  cell_limit, csvGetInput pins max_rows; --max-chars still passed through
- data/flag-defs.json: synced from spec (drops the two flags)
- tests: spot-check moved to --max-chars; dry-run wantInput asserts cell_limit /
  max_rows are pinned high

Mirrors sheet-skill-spec (Base flag records removed).
go build ./... + go test ./shortcuts/sheets/ green.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

shortcuts/sheets/data/flag-defs.json

@@ -1196,15 +1196,6 @@
           "data_validation"
         ]
       },
-      {
-        "name": "cell-limit",
-        "kind": "own",
-        "type": "int",
-        "required": "optional",
-        "desc": "Safety cap; default 5000",
-        "default": "5000",
-        "hidden": true
-      },
       {
         "name": "max-chars",
         "kind": "own",
@@ -1314,15 +1305,6 @@
           "formula"
         ]
       },
-      {
-        "name": "max-rows",
-        "kind": "own",
-        "type": "int",
-        "required": "optional",
-        "desc": "Safety cap; default 100000",
-        "default": "100000",
-        "hidden": true
-      },
       {
         "name": "max-chars",
         "kind": "own",

shortcuts/sheets/flag_defs_test.go

@@ -66,9 +66,9 @@ func TestFlagsFor_MapsAllFields(t *testing.T) {
 		t.Errorf("+sheet-create --url should not be cobra-required: %+v", url)
 	}
 	// hidden + int default
-	cap := byName("+cells-get", "cell-limit")
+	cap := byName("+cells-get", "max-chars")
-	if cap == nil || !cap.Hidden || cap.Default != "5000" {
+	if cap == nil || !cap.Hidden || cap.Default != "200000" {
-		t.Errorf("+cells-get --cell-limit not mapped: %+v", cap)
+		t.Errorf("+cells-get --max-chars not mapped: %+v", cap)
 	}
 	// input sources
 	cells := byName("+cells-set", "cells")

shortcuts/sheets/lark_sheet_read_data.go

@@ -19,6 +19,14 @@ import (
 // The sandbox tool (export_sheet_to_sandbox) is Sheet-Tool-only and has no
 // CLI surface here.
 
+// unboundedReadLimit is pinned into the tool's cell_limit / max_rows so that
+// --max-chars is the single effective read cap. The underlying tools default
+// those two to smaller values; without an explicit high value they could
+// truncate before max_chars. The CLI no longer exposes --cell-limit / --max-rows
+// (only --max-chars), so we pass this sentinel to neutralize the tool defaults.
+// Large enough to never bind on any real sheet.
+const unboundedReadLimit = 1_000_000_000
+
 // CellsGet wraps get_cell_ranges: read multiple A1 ranges and return per-cell
 // values, formulas, styles, and other metadata as requested via --include.
 var CellsGet = common.Shortcut{
@@ -75,9 +83,10 @@ func cellsGetInput(runtime *common.RuntimeContext, token, sheetID, sheetName str
 	if runtime.Bool("skip-hidden") {
 		input["skip_hidden"] = true
 	}
-	if n := runtime.Int("cell-limit"); n > 0 {
+	// --cell-limit was removed from the CLI surface; --max-chars is the single
-		input["cell_limit"] = n
+	// read cap. Pin cell_limit very high so the tool's own default never binds
-	}
+	// before max_chars.
+	input["cell_limit"] = unboundedReadLimit
 	if n := runtime.Int("max-chars"); n > 0 {
 		input["max_chars"] = n
 	}
@@ -172,9 +181,10 @@ func csvGetInput(runtime *common.RuntimeContext, token, sheetID, sheetName strin
 	if runtime.Bool("skip-hidden") {
 		input["skip_hidden"] = true
 	}
-	if n := runtime.Int("max-rows"); n > 0 {
+	// --max-rows was removed from the CLI surface; --max-chars is the single
-		input["max_rows"] = n
+	// read cap. Pin max_rows very high so the tool's own default never binds
-	}
+	// before max_chars.
+	input["max_rows"] = unboundedReadLimit
 	if n := runtime.Int("max-chars"); n > 0 {
 		input["max_chars"] = n
 	}

shortcuts/sheets/lark_sheet_read_data_test.go

@@ -31,6 +31,7 @@ func TestReadDataShortcuts_DryRun(t *testing.T) {
 				"ranges":              []interface{}{"A1:B2"},
 				"include_styles":      true,
 				"value_render_option": "formula",
+				"cell_limit":          float64(unboundedReadLimit), // pinned high; --max-chars is the only cap
 			},
 		},
 		{
@@ -43,6 +44,7 @@ func TestReadDataShortcuts_DryRun(t *testing.T) {
 				"sheet_id":            testSheetID,
 				"range":               "A1:C10",
 				"value_render_option": "formula",
+				"max_rows":            float64(unboundedReadLimit), // pinned high; --max-chars is the only cap
 			},
 		},
 		{